Name
cacosh, cacoshf, cacoshl - complex arc hyperbolic cosineLibrary
Math library ( libm ", " -lm )Synopsis
#include <complex.h> double complex cacosh(double complex z );
float complex cacoshf(float complex z );
long double complex cacoshl(long double complex z );
Description
These functions calculate the complex arc hyperbolic cosine ofz
. If y\ =\ cacosh(z), then z\ =\ ccosh(y). The imaginary part of y is chosen in the interval [-pi,pi]. The real part of y is chosen nonnegative. One has:
cacosh(z) = 2 * clog(csqrt((z + 1) / 2) + csqrt((z - 1) / 2))
Attributes
For an explanation of the terms used in this section, see attributes(7).Interface | Attribute | Value |
T} | Thread safety | MT-Safe |
Standards
C11, POSIX.1-2008.History
C99, POSIX.1-2001. glibc 2.1.Examples
/* Link with "-lm" */ #include <complex.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> int main(int argc, char *argv[]) { double complex z, c, f; if (argc != 3) { fprintf(stderr, "Usage: %s <real> <imag>\en", argv[0]); exit(EXIT_FAILURE); } z = atof(argv[1]) + atof(argv[2]) * I; c = cacosh(z); printf("cacosh() = %6.3f %6.3f*i\en", creal(c), cimag(c)); f = 2 * clog(csqrt((z + 1)/2) + csqrt((z - 1)/2)); printf("formula = %6.3f %6.3f*i\en", creal(f), cimag(f)); exit(EXIT_SUCCESS); }